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PubMed1996

Exposure to environmental complexity promotes recovery of cognitive function after traumatic brain injury.

This study was designed to determine whether exposure to a complex environment after traumatic brain injury (TBI) would promote the recovery of cognitive function. Rats were injured at a moderate level of fluid percussion injury (2.1 atm) or were prepared for injury but were not injured (sham injury). Immediately after the injury or sham injury, the injured/complex (n = 8) and the sham/complex (n = 7) groups were placed into a complex environment. The complex environment was a 89 x 89-cm enclosure with different types of bedding and objects that provided motor, olfactory, tactile, and visual stimulation. The injured/standard (n = 8) and the sham/standard (n = 8) groups were returned to the animal vivarium where they were housed individually in standard wire mesh cages (24 x 20 x 18 cm). On days 11-15 (postinjury), performance in the Morris water maze was assessed. Analysis of the latency to reach the goal platform indicated that injured animals recuperating in the complex environment performed significantly better than injured animals recovering in the standard environment (p < 0.01). In fact, injured animals in the complex environment performed as well as both sham-injured groups. The improved performance of injured rats recovering in the enriched environment occurred in the absence of environmentally induced alterations in brain weight. These results indicate that exposure to environmental complexity enhances recovery of cognitive function after TBI.

Animals↗

PubMed2000

Topographic mapping of P300 and frontal cognitive function in Parkinson's disease.

The purpose of this study was to evaluate the relationship between P300 that is one of the event-related potentials and frontal cognitive functions in Parkinson's disease (PD) without clinically apparent dementia. Subjects were 20 PD cases 48 to 79 years of age, all of whom were within normal limits on the Mini-Mental State examination, and 55 age-matched healthy adults. P300 was elicited with an auditory oddball paradigm and recorded at 15 sites on the scalp. Cognitive functioning of the frontal lobe was evaluated using the New Modified Wisconsin Card Sorting Test (WCST) and the Letter Pick-Out Test (LPOT) which reflects selective attention and semantic categorization. P300 latency was delayed in 30.0% of P300 demonstrated abnormal distribution in 20.0%. the WCST and the LPOT were abnormal in 15.0%, P300 latency significantly correlated with number of subcategories achieved on the WCST. P300 amplitude correlated with scores on the LPOT. These results suggest that cognitive dysfunction which linked partly to the frontal lobe might begin in PD even without clinically apparent dementia.

Journal Article↗

PubMed2006

Cognitive function and behavior of children with adenotonsillar hypertrophy suspected of having obstructive sleep-disordered breathing.

OBJECTIVE: The purpose of this study was to determine whether risks of impaired cognitive function could be predicted for children or groups of children with adenotonsillar hypertrophy who were suspected of having obstructive sleep-disordered breathing, from historical and polysomnographic variables used separately or in combination. METHODS: We studied 114 consecutive 6- to 12-year-old children with adenotonsillar hypertrophy, who were referred because of suspected obstructive sleep-disordered breathing, with questionnaires, assessment of tonsil size, general and memory cognitive tests, and attended polysomnography with the use of nasal pressure recording to detect flow. RESULTS: There were important significant relationships between snore group (snored every night versus less often), sleep efficiency, and race and 2 of 3 general cognitive tests (vocabulary and similarities). Significant but weaker relationships were observed between sleep latency and 2 memory indices (verbal memory and general memory) and between sleep efficiency and 2 behavior indices (attention-deficit/hyperactivity disorder summary and hyperactive-impulsive summary). The number of episodes of apnea and hypopnea per 1 hour of sleep predicted the vocabulary score as well as did the snore group, but it did not predict other tests as well as other variables. Tonsil size did not predict any cognitive or behavior score. Confidence intervals for group means were small, whereas prediction intervals for individual children were large. CONCLUSIONS: Risk of impaired cognitive function and behavior can be predicted from snoring history, sleep efficiency, sleep latency, and race but not tonsil size. The combination of snoring history and polysomnographic variables predicted impaired cognitive scores better than did either alone. The snoring history predicted more test scores than the number of episodes of apnea and hypopnea per 1 hour of sleep.

Adenoids↗

PubMed2000

Massive impairment in executive functions with partial preservation of other cognitive functions: the case of a young patient with severe degeneration of the prefrontal cortex.

Historical bases for the special role of the prefrontal cortex are outlined and the case of a 27-year-old woman with massive bilateral prefrontal damage of unknown etiology is then described. Frontal lobe degeneration was repeatedly examined with magnetic resonance imaging and fluoro-deoxy-D-glucose-positron emission tomography and was found to include both orbital and dorsolateral aspects of the frontal lobes. While the degeneration initially measured was limited to portions of the orbital, medial and dorsolateral parts of both frontal lobes, with right-sided predominance, a second brain scan 15 months later revealed massive shrinkage of both frontal lobes, together with additional involvement of the posterior association cortices. The patient had completed her high-school education and had superior verbal long-term memory, normal short-term memory, and normal priming, but manifested grossly deficient scores in various frontal lobe-sensitive tests. Though a number of neurological examinations were performed, no plausible cause for the damage was established.

Adult↗

PubMed2005

Recovery after prolonged sleep deprivation: residual effects of slow-release caffeine on recovery sleep, sleepiness and cognitive functions.

A long work schedule often results in sleep deprivation, sleepiness, impaired performance and fatigue. We investigated the residual effects of slow-release caffeine (SRC) on sleep, sleepiness and cognitive performance during a 42-hour recovery period following a 64-hour continuous wakefulness period in 16 healthy males, according to a double-blind, randomised, placebo-controlled, crossover study. Three hundred milligrams of SRC or placebo was given twice a day at 21:00 and 9:00 during the first 48 h of wakefulness. Recovery sleep was analysed with electroencephalography (EEG) and wrist actigraphy, daytime sleepiness with continuous EEG, sleep latency tests and actigraphy and cognitive functions with computerized tests from the NATO AGARD STRES battery. Both drug groups exhibited almost the same sleep architecture with a rebound of slow-wave sleep during both recovery nights and of REM sleep during the second night. Wakefulness level and cognitive functions were similarly impaired in both groups on the first day of recovery and partially returned to baseline on the second. To conclude, SRC appears to have no unwanted side-effects on recovery sleep, wakefulness and cognitive performance after a long period of sleep deprivation and might therefore be a useful choice over other psychostimulants for a long work schedule.

Adult↗

PubMed1998

Effect of oxygen on sleep quality, cognitive function and sympathetic activity in patients with chronic heart failure and Cheyne-Stokes respiration.

BACKGROUND: Cheyne-Stokes respiration disrupts sleep, leading to daytime somnolence and cognitive impairment. It is also an independent marker of increased mortality in heart failure. This study evaluated the effectiveness of oxygen therapy for Cheyne-Stokes respiration in heart failure. METHODS: Eleven patients with stable heart failure and Cheyne-Stokes breathing were studies. Oxygen and air were administered for 4 weeks in a double-blind, cross-over study. Sleep and disordered breathing was assessed by polysomnography. Symptoms were assessed using the Epworth Sleepiness Scale, visual analogue and quality of lift scores. Cognitive function was assessed by neuropsychometric testing. Overnight urinary catecholamine excretion was used as a measure of sympathetic nerve activity. RESULTS: Ninety-seven percent of apnoeas were central in origin. Oxygen therapy reduced the central apnoea rate (18.4 +/- 4.1 vs 3.8 +/- 2.1 per hour; p = 0.05) and periodic breathing time (33.6 +/- 7.4 vs 10.7 +/- 3.9% of actual sleep time; p = 0.003). Oxygen did not improve sleep quality, patient symptoms or cognitive failure. Oxygen reduced urinary noradrenaline excretion (8.3 +/- 1.5 vs 4.1 +/- 0.6 nmol.mmol-1 urinary creatinine; p = 0.03). CONCLUSION: Oxygen stabilized sleep disordered breathing and reduced sympathetic activity in patients with heart failure and Cheyne-Stokes respiration. We were unable to demonstrate an effect on either patient symptoms or cognitive function.

Aged↗

PubMed1991

Cognitive function in children with leukemia. Effect of radiation dose and time since irradiation.

The effect of two cranial radiation (CRTX) doses and the time since radiation therapy on cognitive functioning were studied in 35 children who completed therapy for acute lymphoblastic leukemia (ALL). The patients were grouped according to CRTX dose (2400 or 1800 cGy) and evaluated for general intelligence, academic achievement, and visual motor integration. Those who received 2400 cGy (n = 20) scored ten points below those treated with 1800 cGy (n = 15) on verbal intelligence quotient and achievement tests of reading, spelling, and arithmetic. The effect of time since radiation therapy on these measures of cognitive function was significant (P = 0.001 to 0.03); the effect of CRTX dose was not. Visual motor integration scores in both groups fell below the 33rd percentile. The effect of CRTX dose and time since radiation therapy on visual motor integration and performance intelligence quotient were not significant. Thus, the interval between treatment and the emergence of cognitive impairments may be longer after lower CRTX doses, and deficits in nonverbal areas such as visual motor integration may appear first. A larger study is needed to confirm these findings from a limited sample of long-term survivors of ALL.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1997

Assessment of cognitive function. A study with the Swedish version of the Kaufman Assessment Battery for Children.

The Kaufman Assessment Battery for Children (K-ABC) is a test that measures cognitive function in children. A Swedish version has been produced for use as a research instrument in a longitudinal follow-up study of children that needed neonatal intensive care at the Uppsala University Children's Hospital, Sweden. A study using this Swedish version was carried out in 26 healthy children 10 years of age attending a primary school in Uppsala, Sweden. The results showed that the Swedish version of the K-ABC well discriminates cognitive function in children aged 10 years. The scores of all subtests were distributed over the scale and the mean scores mostly corresponded to near average or above average performance when compared with the mean values obtained in the standardization sample.

Child↗

PubMed2026

Effects of six weeks of guanidinoacetic acid supplementation with and without creatine monohydrate on cognitive function and markers of health in healthy adults.

BACKGROUND: Guanidinoacetic acid (GAA) supplementation has been reported to increase brain creatine content more effectively than creatine monohydrate (CrM). However, the effects on cognitive function are unclear. PURPOSE: The purpose of this proof-of-concept exploratory clinical trial was to determine whether GAA supplementation with and without CrM affects cognitive function and/or markers of health. METHODS: In a double-blind, randomized, and counterbalanced manner, 58 healthy and active adults (33 females, 35.5 ± 14 years, 76.2 ± 14 kg) ingested a PLA (PLA, 2 × 6 g/d maltodextrin), GAA (2 × 1 g/d) + PLA (2 × 5 g/d), or GAA (2 × 1 g/d) + CrM (2 × 5 g/d) for six weeks. The participants donated fasting blood samples and completed a battery of tests and questionnaires assessing various aspects of function, mood, stress, sleep quality, and markers of health at baseline and after six weeks of supplementation. Data were analyzed using General Linear Model (GLM) multivariate and univariate with repeated measures, and mean changes from baseline with 95% confidence intervals, and Chi-squared analysis, and considered significant when the probability of error was 0.05 or less, and approaching significance (p > 0.05-p < 0.10). RESULTS: GAA supplementation tended to improve overall reaction time (-241.8 ms [-533, 50], p = 0.10) while significant interaction effects were observed in overall reaction time (p = 0.031-330 ms [-629, -31]) and YES reaction time (-290 ms [-484, -96], p = 0.004) while recalled correct reaction time (-178 ms [-374, 21], p = 0.078) and recalled correct YES (7.4 % [-1, 15.8], p = 0.084) approached significance compared to PLA. Limited to no effects were observed on the Delayed Picture Recognition Task Test, Digit Vigilance Task Test, Corsi Block Task Test, or Stroop Color-Word Task Test. The amount of time engaged in moderate physical activity was significantly greater (p < 0.05) in the GAA group compared to PLA. Participants in the GAA group reported a lower frequency of controlling irritations (p = 0.036), and feeling like difficulties are mounting (p = 0.053) on the Perceived Stress Scale. Some positive and potentially undesirable effects were observed in sleep quality assessments. The quality of life assessment revealed that participants in the GAA group reported less frequent feelings of being worn out (p = 0.068) and that their health was excellent (p = 0.092) while those in the GAA + CrM group reported more frequent limitations when bending, kneeling, or stooping (p = 0.053), more often feeling full of life (p = 0.081), and less frequency in feeling downhearted and depressed (p = 0.066). No clinically meaningful changes were observed in blood markers or self-reported side effects among the groups. CONCLUSION: Dietary supplementation with GAA (2 g/d) and the combination of CrM (10 g/d + GAA 2 g/d) for six weeks improved delayed verbal episodic recognition memory and retrieval speed and some measures of perceived stress, sleep quality, and quality of life. However, most cognitive tests were not affected, particularly when comparing the GAA to the PLA group; there were some inconsistencies in the findings, and several differences only approached significance. Additional research is needed before conclusions can be drawn. Clinical trial registration: ISRCTN68542582.

Humans↗

PubMed2005

Non-linear relationships between cognitive function and alcohol consumption in young, middle-aged and older adults: the PATH Through Life Project.

AIMS: To investigate associations, including non-linear relationships, between cognitive function and alcohol consumption, testing for moderating effects of age and gender and for differences across outcome measures. Design Cross-sectional general population samples of three age cohorts. Setting Canberra and Queanbeyan, Australia. PARTICIPANTS: The total sample of 7485 consisted of 2404 men and women aged 20-24 years, 2530 aged 40-44 years, and 2551 aged 60-64 years, selected from the electoral rolls. Measurements Self-report data using hand-held computers provided weekly alcohol consumption from the Alcohol Use Disorders Identification Test (AUDIT) frequency, quantity and binge-drinking items, and socio-demographic factors. Spot-the-Word, digits backwards, the Symbol-Digit Modalities Test (SDMT), immediate recall and reaction-time tests were conducted by trained interviewers. FINDINGS: Findings varied across dependent variables, but there was a general tendency for light drinkers (up to 20/10 g alcohol per day in men/women, respectively) to perform better than abstainers, occasional drinkers or those drinking at hazardous/harmful levels (>40/20 g per day in men/women). Poorer performance of hazardous/harmful drinkers was seen only in men, whereas that of abstainers was evident in both sexes but was stronger in women. After adjustment for education and race, male hazardous/harmful drinkers no longer performed significantly less well than light drinkers, whereas male and female abstainers and occasional drinkers still did so. CONCLUSIONS: Abstainers have poorer cognitive function than light drinkers and further investigation is needed to determine what factors contribute to this.

Adult↗

PubMed2000

Adaptation of cognitive function to hypoglycemia in healthy men.

OBJECTIVE: Antecedent hypoglycemia reduces hypoglycemic counterregulation and symptoms, thereby provoking the hypoglycemia unawareness syndrome. The effects of antecedent hypoglycemia on hypoglycemia-induced cognitive dysfunction are less well established. RESEARCH DESIGN AND METHODS: To determine whether antecedent hypoglycemia also reduces hypoglycemic cognitive dysfunction, we performed stepwise hypoglycemic clamp experiments (4.1, 3.6, 3.1, and 2.6 mmol/l) during a 6-h period in 30 young healthy men. A total of 15 subjects additionally received a 2.5-h antecedent hypoglycemic clamp (3.1 mmol/l) on the preceding day (prior-hypo group), whereas the other 15 subjects did not (control group). Cognitive function was assessed by auditory-evoked brain potentials (AEBPs) and reaction time during a vigilance task and short-term memory recall. Tests were performed during the stepwise hypoglycemic clamp at baseline and at each hypoglycemic plateau. RESULTS: In both groups, performance on all measures of cognitive function deteriorated during stepwise hypoglycemia (all P < 0.01). However, after antecedent hypoglycemia, the hypoglycemia-induced decrease in the amplitude of the P3 of the AEBP was distinctly reduced compared with the control condition (P < 0.05). Also, short-term memory performance was less impaired in the prior-hypo group than in the control group (P < 0.005), and a minor hypoglycemic impairment of reaction time (P < 0.05) was evident in the prior-hypo group. CONCLUSIONS: Data provide evidence that a single episode of mild antecedent hypoglycemia (3.1 mmol/l) attenuates several aspects of cognitive dysfunction during subsequent hypoglycemia 18-24 h later.

Adaptation, Physiological↗

PubMed1998

A prospective study of cognitive function and onset of dementia in cognitively healthy elders.

OBJECTIVE: To examine the earliest cognitive changes associated with the onset of dementia as well as changes associated with normal aging. DESIGN: Longitudinal evaluation of participants with annual clinical and psychometric examinations for up to 15 1/2 years. SETTING AND PARTICIPANTS: Elderly volunteers (n = 82) enrolled with a Clinical Dementia Rating of 0 (cognitively intact) in longitudinal studies. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Clinical Dementia Rating and results of a 1 1/2-hour psychometric battery. RESULTS: As estimated with survival analysis, 40% of participants had a Clinical Dementia Rating greater than 0 (cognitive decline) within 12 years of enrollment; 59% of these were judged to have dementia of the Alzheimer type or incipient dementia. Participants with poorer performance on psychometric testing at enrollment were at higher risk for cognitive decline subsequently. The rate of change in psychometric performance before clinically detectable cognitive change occurred was not significantly different between those who eventually developed dementia and those who remained stable, except for performance on the Logical Memory subtest of the Wechsler Memory Scale. When subtle cognitive decline was clinically detected, however, an abrupt deterioration in performance on independently administered psychometric tests was observed. CONCLUSIONS: Cognitively healthy elderly people maintain stable cognitive performance when measured longitudinally by both careful clinical evaluation and repeated psychometric testing. This stability is maintained unless and until they develop a dementing illness, at which time a sharp decline in performance is observed.

Aged↗

PubMed1982

The neuropsychology of cognitive function.

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Brain↗

PubMed1993

Blood pressure and cognitive function in healthy old people.

OBJECTIVE: Since hypertension is a major risk factor for multi-infarct dementia, this study aimed to evaluate the effect of blood pressure on cognitive function in elderly subjects on no medication and disease-free. DESIGN: A cross-sectional survey. SETTING: Community. PARTICIPANTS: 598 healthy community-resident subjects aged 70 years and over who were on no treatment. MEASUREMENTS: Blood pressure (BP) and MMSE score, an index of cognitive function. RESULTS: Mean age of the sample was 75.7 years, mean BP 160/86 mmHg, mean MMSE 28.0. Systolic BP correlated negatively with MMSE (P < 0.05), but diastolic BP showed no significant overall correlation. To study possible J-shaped curve effects of BP, the sample was stratified into three groups--low BP, normal BP, and high BP--at levels one standard deviation from the mean for both systolic and diastolic pressures. Mean MMSE scores for low, normal and high systolic BP were 28.3, 28.1, 27.5, respectively; for low, normal, and high diastolic BP scores were 28.0, 28.1, and 27.5 respectively. Multivariate analysis of variance found the differences between normal and high to be significant at P < 0.001 for systolic and P = 0.001 for diastolic BPs. CONCLUSION: High blood pressure is associated with cognitive impairment in healthy, drug-free, older people.

Aged↗

PubMed1982

Early cognitive functioning: sex and race differences.

Six scales of early cognitive functioning were administered at three times (eight months, four and seven years) to 3013 black and white, male and female children. Hypotheses addressed the nature and extent of longitudinal sex differences in cognitive abilities among racial groups varying in physical maturation. Controlling for selected socioeconomic influences, a slight sex by race interaction was found at four and seven years. Generally, white females scored somewhat lower on cognitive tests than white males, whereas black females scored equivalently or somewhat higher than black males. Test score differences among the four sex and race groups were more apparent in seven-year spatial abilities relative to verbal abilities. Findings are discussed in terms of possible maturational and environmental influences on cognitive abilities among different sex and race groups.

Child↗

PubMed2006

Assessment of cognitive function in the heterozygous reeler mouse.

RATIONALE: The heterozygous reeler mouse has been proposed as a genetic mouse model of schizophrenia based on several neuroanatomical and behavioral similarities between these mice and patients with schizophrenia. However, the effect of reelin haploinsufficiency on one of the cardinal symptoms of schizophrenia, the impairment of prefrontal-cortex-dependent cognitive function, has yet to be determined. OBJECTIVE: Here, we investigated multiple aspects of cognitive function in heterozygous reeler mice that are known to be impaired in schizophrenic patients. METHODS: Heterozygous reeler mice were assessed for (1) cognitive flexibility in an instrumental reversal learning task, (2) impulsivity in an inhibitory control task, (3) attentional function in a three-choice serial reaction time task, and (4) working memory in a delayed matching-to-position task. RESULTS: No differences were found between heterozygous reeler mice and wild-type littermate controls in any prefrontal-related cognitive measures. However, heterozygous reeler mice showed deficits in the acquisition of two operant tasks, consistent with a role for reelin in certain forms of learning. CONCLUSIONS: These findings suggest that heterozygous reeler mice may not be an appropriate model for the core prefrontal-dependent cognitive deficits observed in schizophrenia, but may model more general learning deficits that are associated with many psychiatric disorders.

Animals↗

PubMed2006

High-sensitivity C-reactive protein and cognitive function in older women.

BACKGROUND: Inflammatory processes may be involved in the development of dementia, although findings from epidemiologic studies directly examining inflammatory markers and dementia or its precursor, impaired cognitive function, are inconsistent. METHODS: We measured plasma levels of the inflammatory marker, C-reactive protein, using a high-sensitivity assay (hs-CRP) in 4,231 older participants of the Women's Health Study, who provided blood samples between 1992 and 1996 when they were age 60 to 90 years. From 1998 to 2000, we administered a battery of 5 cognitive tests measuring general cognition, verbal memory, and category fluency. Using multiple linear regression, we compared mean cognitive test scores across quintiles of hs-CRP, adjusting for potential confounding factors. RESULTS: There was a wide distribution of hs-CRP levels among these women, and a large proportion had levels considered to reflect a high risk of cardiovascular disease. We observed no suggestion, however, that higher hs-CRP levels were associated with poorer cognitive performance. For example, on a global score combining results of all the cognitive tests, mean scores among women in the highest quintile of hs-CRP did not differ from those in the lowest quintile (multivariable-adjusted mean difference = 0.04; 95% confidence interval [CI]: -0.02 to 0.11, P for trend across quintiles = 0.38). CONCLUSION: Overall, in these women, we found no evidence of a link between hs-CRP, a marker of inflammation, and decrements in cognitive function.

Aged↗

PubMed1993

Cognitive functions and brain structures: a quantitative study of CSF volumes on Alzheimer patients and healthy control subjects.

In the present study we have investigated the connection between cerebrospinal fluid spaces and cognitive function in patients with senile dementia of Alzheimer type (SDAT) and in successfully aged control subjects. The cerebrospinal fluid (CSF) volumes were measured using a low field MRI technique, and the cognitive functions were assessed with a number of psychometric tests. We found that the SDAT patients showed significantly larger relative volumes in all examined CSF spaces. The largest differences between the groups were found in the volumes of the temporal horns. We also found a significant correlation between the relative CSF volumes in the basal parts of the brain, and episodic memory tests. Significant correlations were also detected between the relative volumes of the lateral ventricles, and degree of dementia as well as between the relative volumes of the lateral ventricles and episodic memory tests.

Aged↗